Pure sine wave inverters true to its rated wattage

[lonewolf2koc]

I'm looking for a decent pure sine wave inverters with wired remote with close to the claimed wattage. The budget is $300 or less. Not going to spend $400 or more on this. So far the Whistler 400W mod sine wave is giving up only with a 200W load over and over. I tried with the Lakso 200W heater. Shut down after 1 hr. Then later a Mac Book Pro, couple ext USB3 hard drives (about 160W). And it too shut down just only 50% of the rated capacity. That inverter still works as long as I'm using 1/3 or 1/4 of the max.

Now trying out the Micro Solar 1000W pure sine wave. It's able to handle 200-250W so far. That's roughly 1/4 of its rated wattage. But I don't like it due to its huge size. Very hard to fit in a tight mini van.

To be on the safe side, I'll have to subtract 25-50% from the rated wattage from these current crops of Chinese made inverters. A 1000W to me is roughly can only handle 500-600W sustained load over long period of times (24-72 hours). This has yet to be fully tested in real load scenarios. So far only 1/4 of the max load tested. I don't know about others but that what I'm experiencing from the past 2-3 inverters purchased. Maybe I didn't pay enough for a high quality one.

 

[BradKW]

I would think something like this Morningstar for $245 would be what you looking for... http://www.invertersrus.com/morningstarsuresinesi-300-115v.html

I believe that if you go with Morningstar or Magnum to best fit your budget, you will get the best results...but may find your budget doesn't get you enough wattage. After reading reviews, blogs and forums for past few weeks on inverters, it appears that many of the manufacturers that used to hold a decent reputation have farmed out to the Chinese.

I also remember reading something about electric heaters being run on inverter. I can't recall why, but it wasn't suggested...so take that for what its worth

 

[speedhighway46]

Hello Lonewolf:

I've had a Chinese inverter rated at 3000 watts in my truck conversion motor home for about three years. When I purchase something made in China I also expect the least; high failure rate; not performing to specs; difficult to get replacement parts; etc; etc. The only reason I purchase Chinese-made items is because: 1) that's all there is, or 2) they're cheap.

I have never loaded this inverter to maximum rate, but I have had it up to 1500 watts and it's still working. It's fed directly from the house batteries, a short run of parallel 4 gauge on both positive and negative. I've run all sorts of loads on it including power tools and electric heaters.

When I bought the unit off eBay it was intended to be a temporary thing, before upgrading to a quality unit costing $1500-2000. As long as this one continues to work I'll use it.

As a suggestion, make sure you are using the heaviest power cables you can afford and that your inverted is positioned as close to the battery bank as you can get it. This will provide current carrying capacity high enough to support the output specs of the inverter, and will also minimize voltage drop. Fuse at least the battery end of the cable.

I have always been a believer in you get what you pay for.

My next big electrical project is a solar panel array on my roof. I'll start that in the spring, I hope.

Best of luck with your inverter project!

 

[blars]

Are you sure your problem isn't the inverters cutting out due to low voltage input due to inadiquate wiring or battery? Measure the voltage at the inverter input terminals when under load. A big inverter needs big thick short wires to a heafty battery bank. LiFePO4 and AGM do better than traditional Lead-acid under this type of usage.

 

[GotSmart]

Are you sure your problem isn't the inverters cutting out due to low voltage input due to inadiquate wiring or battery?  Measure the voltage at the inverter input terminals when under load.  A big inverter needs big thick short wires to a heafty battery bank.  LiFePO4 and AGM do better than traditional Lead-acid under this type of usage.

X2!

Also make sure of clean and tight connections.

In setting up my system I spent $100 on tools and top quality wire and connectors before I started. 

In reviewing things, a lot more than that!  I have not had one problem with the system I installed. Perhaps because I listened to Sternwake. 

https://vanlivingforum.com/Thread-12-volt-components

 

[lonewolf2koc]

The Whistler 400W mod sine wave I got came bundled with a very thin AWG wire. If I'm not mistaken, 400W AC load on that inverter will need roughly 33 A (400/12=33) in DC. That would translate to roughly a 10 AWG wire on my solar panel below 10 ft run. I'm seeing the supplied cable to be very thin, something like 14-12 AWG range. Will try out 8 AWG sized wires to see if that's the culprit.

When I get to 8 or higher wire gauge, I prefer to use a offset bolt with removable screw to tighten the exposed wires (found at Home Depot) vs crimping with a round or spade type of lug. Much more hand muscle power and expensive hydraulic tools needed to do the job (particularly 1/0 and larger). Plus with the mechanical offset screw lug, I can easily unscrew the wire and move it to a different battery, joining several other connections to the same battery post.

X2!

Also make sure of clean and tight connections.

In setting up my system I spent $100 on tools and top quality wire and connectors before I started. 

In reviewing things, a lot more than that!  I have not had one problem with the system I installed. Perhaps because I listened to Sternwake. 

https://vanlivingforum.com/Thread-12-volt-components

 

[speedhighway46]

A follow up to my previous post.

TSC (Tractor Supply) stores sell a nice assortment of copper crimp-on battery lugs. It's all I've used on my truck conversion project and they have worked great. They come in several different sizes depending on the gauge wire you are using. Most of my stuff is 2, 4, and 6 gauge.

Having trouble attaching heavy duty high-current battery lugs? Harbor Freight sells an hydraulic hand crimped for around $40. Best tool I ever bought from HF! Works perfect; I have made 100's of crimps with this tool and it works like new.

 

[SternWake]

I run a 200 watt Lasko heater off of a Wagan Elite 400 watt PSW inverter.  It is about a 19 amp draw at 12.2v.

http://www.amazon.com/Wagan-EL2601-...id=1448126444&sr=8-1&keywords=wagan+elite+400



Depending on how much battery capacity you have, this is a big load and you should not expect small battery capacity to power it for very long.

Also, large loads are when mr Peukert steps in and reduces the overall battery capacity available.  I only run that heater under my blankets for 15 to 20 minutes till the bed is warmed up, and even this is abusive to my single 90AH agm battery.

200 watts of heater does very little in my lightly insulated Van, and is a huge load on a battery bank.  My 400 Watt inverter has no issue whatsoever running it, but my battery capacity simply is not large enough to run it for long, and it simply does not do that much in terms of actually heating the van.  Even when I am plugged in and run the thing all night long, if it is high 30's outside, It is barely mid 50's inside, and I would need 3x the battery capacity to power it overnight, and 5x as much solar to return everything the ineffective heater consumed.

Crushing stranded wire with a bolt nut and washer is makes for a horrid electrical connection which will have a lot of resistance and degrade quickly.  Steel is not a good conductor.  Exposed copper stranding oxidizes quickly and develops higher resistance.  Such electrical connections should not be viewed as temporary and moved back and forth.

Don't cheap out on electrical connections, you can't save money here.  The Hydraulic crimpers have come way down in price, and now the leverage crimpers are quite affordable too.  Don't cheap out on the ring terminals wither, like the Pico ones sold on Amazon.  They are very thin copper and defeat the purpose of having a good solid crimped ring terminal

 http://www.amazon.com/Iwiss-Crimper..._UL160_SR160,160_&refRID=0EXN1TV66AAWGEVCE46E


My Wagan came with a ciggy plug cord with a 120 watt maximum rating on it, and they are smoking crack thinking anything more than 60 watts is safe long term through the  cheapo ciggy plug provided, and it also came with a pair of 10awg leads about 2.5 feet long.  I use about half that length.

The Wagan has no remote.  My 800 watt MSW inverter, I ran a remote toggle switch 6 feet away to turn the inverter on and off from Bed, but have since wired it back up normally, and just let the Wagan chew up 0.25amps per hour when unloaded.  My 800watt's fan was too loud and annoying to leave running when not actually powering anything.  I can't hear the Wagan's fan until about 250 watts and it is silent when unloaded.

I have load tested this Wagan 400watt inverter.  It was able to sustain a 440 watt load when I had short 10awg wiring to the fuse block and bussbar.  It was able to sustain only 320 watts when I used the full length of 10awg provided, and had a crappier connection at the battery .  I have not put it on an oscilloscope or checked its output voltage under load though, so am not sure how well it performs here, all I can say is it powered more than its rating successfully, but the casing did get very hot and the fan was running at full speed and sounded a bit sick.

The Wagan 400 watt unit is a very small compact inverter, which is one of the reasons I like it.

Do not underestimate the importance of a good electrical connection.  Voltage drop is the nemesis and really has a huge effect on high loads that an inverter can demand.

 

[Optimistic Paranoid]

As I'm sure you know, electric motors require a higher amount of power to get them spinning from standstill than they need to keep them running once they are up to speed.

Many inverters are capable of BRIEFLY handling this higher starting load.  Unfortunately, many less than scrupulous companies take advantage of this to advertise the amount of watts of stating power it can provide, rather than the lower amount of CONTINUOUS power they can deliver. 

One company that doesn't play that game is Morningstar.  Their Suresine 300 provides an honest 300 watts of continuous pure sine wave power, and is capable of briefly handling up to 600 watts while starting motors.

Regards
John

 

[Sabatical]

We use a 1000 watt psw Go Power inverter in the kitchen of our tiny house on wheels. We use it because it's what we had. It's not small and it's a tad more than $300. I would gladly swap a smaller wattage one out for this one but selling one of these second hand isn't easy. The inverter powered the a/c recptacles in our last camper and we regularly ran a 650 watt spin dryer plugged into an outside receptacle with no issues. It however does not like the high end of absorb cycle voltage and would beep it's complaints at us. I think the key to our success with it was that it was fed by 2 gauge in the camper. It's currently fed with 4 gauge but doesn't see much for loads (kitchen-aid or food processor)
When i was shopping for a new inverter for our smaller camper i looked and looked. Despite all the on line advice i got a 1000 watt msw Bestek. It is smaller by half in size compared to the go power. I wired it the same as the go power was wired in the previous camper, into the power center of the camper so that all receptacles would be hot with the inverter on. It works fine. It powers the spin dryer plugged in to the outside receptacle. It also charges cordless drill batteries. I would have liked to get another psw but cost and space were just not in our budget.